It is known to use alternative fuels for the operation of motor vehicles such as passenger cars, lorries and busses. In this respect, the use of compressed natural gas, in particular, has proven to be a practical and low-emission alternative in comparison to the operation with petroleum-based fuels. For the operation with natural gas, the motor vehicle carries a high-pressure natural-gas tank. The natural gas is delivered to combustion engine via a fuel supply system. Vehicles with natural gas tank systems or other high-pressure tank systems based on gaseous or liquefied fuels require special refueling facilities, such as provided for example in CNG (“compressed natural gas”) or LPG (“Liquefied Petroleum Gas”) filling stations.
Generally speaking the use of compressed gas due to the high pressures present in the tank system may involve hazards in case of damages or malfunctions. In order to avoid such hazards it has proven advantageous to safeguard the tanks against excessive temperatures and excessive pressures. The associated safety devices are, as a rule, arranged in the high-pressure tank valves. US 2010/0307454 A1 describes a method for distributing the fuel within a fuel system of a motor vehicle. The method is applicable to a tank system which includes a first fuel tank, in which the fuel is compressed to a first pressure, and a second fuel tank, in which the fuel is compressed to a second pressure, wherein the second pressure is higher than the first pressure. The method includes steps, in which fuel already filled into the second tank is fed into the first tank, and fuel is filled into the first tank and the second tank at the same time.
It is a requirement in the art to provide sufficient safety in respect of excessive pressures and temperatures for a high-pressure tank system of motor vehicles on the one hand, and on the other, to improve the profitability and efficiency of the safety devices to be used therein.